1. Field of the Invention
The present invention relates to a VR resolver (Variable Reluctance resolver) having a specific structure at a terminal portion to which a stator coil is connected.
2. Description of Related Art
Variable reluctance resolvers (VR resolvers) used for measurement of a rotating position are known. The VR resolver is formed by arranging a rotor, which is made of a magnetic material, in a stator. The stator has plural magnetic salient poles that are projected from a circular stator core toward a rotation center and that are wound with wires. The stator of the VR resolver has the following general structure. The stator core is formed by laminating plural circular yoke sheets that are formed by press cutting soft magnetic materials. The stator core is held between a pair of plastic resin insulators from top and bottom sides in an axial direction. While the pair of insulators insulates the stator core, the salient poles are wounded with wires, whereby a stator coil is formed of an exciting coil, a sine phase detection coil, and a cosine phase detection coil.
The rotor has plural convex portions corresponding to the salient poles of the stator core. While the rotor rotates, a distance between an outer circumferential surface of the rotor and each of the sine phase detection coil and the cosine phase detection coil, is periodically changed. In this case, if electric current is supplied to the exciting coil, induced currents induced by the sine phase detection coil and the cosine phase detection coil are periodically changed according to rotation angle of the rotor. By measuring the induced currents induced by the sine phase detection coil and the cosine phase detection coil, the rotation angle of the rotor is calculated at an RD converter (Resolver-digital converter). The insulator is provided with a terminal portion, and the terminal portion has terminal pins for outputting signals that are detected by the sine phase detection coil and the cosine phase detection coil, to the outside. End portions of the stator coil are connected with the terminal pins (For example, see Japanese Unexamined Patent Application Laid-open No. 2009-27841).
In the structure of the above terminal portion, the terminal pins are exposed. Therefore, when external load is applied to the terminal pins by contacting with other members, there is the possibility of deformation of the terminal pins and disconnection of lead portions of the windings. Moreover, there is the possibility of shorting and contact failure due to a drop of water, dust, or dirt, which enters between the adjacent terminal pins from the outside.